1. Field of the Invention
This invention relates to an impregnating waterproof composition having algae controlling ability and resistance against water absorption.
2. Prior Art
Most impregnating waterproof compositions known in the prior art are based on an organo-alkoxysilane or a hydrolyzate thereof or a cohydrolyzate thereof with another organic silicon compound having a hydrolyzable silyl group. See Japanese Patent Application Kokai Nos. 236581/1988, 44673/1989 and 212287/1989, German Patent Nos. 2,029,446 and 2,258,901, and U.S. Pat. Nos. 4,433,013 and 4,455,172.
These organoalkoxysilane based compositions are applied to substrates of inorganic material such as cement concrete, mortar, blocks, slates, bricks, tiles, roof tiles, gypsum and other masonry to penetrate through pores therein whereupon the composition forms a three dimensional structure while bonding to the substrate in each pore for forming a long-lasting waterproof layer. The compositions are thus widely used as waterproof sealants to inorganic materials because of high durability and reliability as compared with conventional well-known waterproof materials based on organic polymers such as epoxy, acryl and urethane resins and water-repellent materials based on methyl siliconate aqueous solutions.
Despite the above-mentioned advantages, the organo-alkoxysilane based compositions tend to be soiled with algae and fungi since the compositions are not effective for controlling growth of algae and fungi.
Several substances are known to control algae growth. When applied to the surface of inorganic materials, the conventional anti-algae agents are effective only for some initial time, but tend to slip away from the inorganic material surface through extraction by water upon rainfall or the like. This is because these anti-algae agents simply adhere to the inorganic material surface.